A new study by a group of scientists from the USA and Great Britain suggests that people with dementia are vulnerable to coronavirus not only because of their age and problems with remembering safety precautions.
In an article in the Journal of Gerontology, researchers emphasize that most elderly patients who died from coronavirus in England and Wales suffered from dementia. This made scientists think that it was not only social factors, but also genetic mutations.
They analyzed information from the British Biobank, which collected medical and genetic data from 500,000 volunteers aged 48 to 86 years. The team focused on the ApoE gene, which encodes the apolipoprotein E protein, which plays an important role in lipid metabolism. It is known that one of its variants “e4” affects cholesterol levels and processes associated with inflammation, and also increases the risk of heart disease and dementia.
Researchers found that out of 383,000 participants in Biobank of European descent, 9,022 had two copies of the e4 option, while more than 223,000 had two copies of the e3 option. Scientists noted that the first group has a 14-fold higher risk of dementia than the second.
The group then examined positive tests for COVID-19, obtained between March 16 and April 26, when testing for coronavirus was conducted primarily in hospitals. It turned out that 37 people with a confirmed diagnosis had two copies of the “e4” ApoE variant, while 401 patients had two copies of the “e3” variant. Taking into account various factors, including the age and gender of the patients, the researchers stated that in people with two “e4” options, the risk of severe COVID-19 was twice as high as in patients with two “e3” options.
According to co-author of the study, professor of epidemiology and public health at Exeter University, David Melzer, this relationship was confirmed even after the team excluded participants with confirmed dementia from the study.
Professor Tara Spires-Jones, an expert on neurodegeneration at the University of Edinburgh who did not participate in the study, noted a strong association between genetic variants of ApoE and the risk of severe COVID-19. But, according to her, despite the importance of this discovery, the study does not yet prove that it was genetic mutations that caused complications in coronavirus.
"It is possible that the role of ApoE plays a large role in the functioning of the immune system in the disease, and future studies will be able to use this data to develop effective treatments," said the professor.
Fiona Carragher, director of research and influence at the Alzheimer's Society, said the British with dementia and their loved ones were desperate when, at the peak of the epidemic, these people began to get sick and die en masse. According to her, scientists should continue research, and authorities should take urgent measures to protect this vulnerable group of patients.
“You need to understand why people with dementia are at higher risk and to what extent various factors, such as genetics or ethnicity, influence it,” Carragher said.
In mid-April, an international group of experts led by the Dementia Care and Research Center at Peking University Institute of Mental Health warned of a “double hit” pandemic for elderly patients with this diagnosis. According to experts, these people are especially vulnerable now, because they not only fall into the risk group by age, but also have problems remembering safety rules and having to stay at home.
Scientists also noted that older people in many countries live alone, with a spouse, or in a nursing home. Many companies that provide various services to older people are now unable to work. As a result, patients with dementia who need the services of home assistants find themselves alone and feel abandoned. In addition, visits to nursing homes are now banned in many countries, which is why old people suffer from social exclusion and staff are under great stress.